Chrysler 8 3/4 Axle bearing and Seal R&R...A How To

khryslerkid

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Great info on here. I just pulled my rear out as this is the third time I will replace the drivers side inner seal. Sure enough, the two thrust buttons and broken pin were sitting in the bottom of my pumpkin. This of course allowed the drivers side axle way too much play back and forth ruining the inner seal. My question is: Will I have to replace that broken pin to keep them in place or if I am real careful on installation will the thrust buttons stay in place? Thanks!

The axle will hold them in place unless the axle is pulled out again. They stick to the end of the axle when pulling it out. Dr. Diff has new ones with the pin that holds the buttons together.
 
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440 Charger

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Great info on here. I just pulled my rear out as this is the third time I will replace the drivers side inner seal. Sure enough, the two thrust buttons and broken pin were sitting in the bottom of my pumpkin. This of course allowed the drivers side axle way too much play back and forth ruining the inner seal. My question is: Will I have to replace that broken pin to keep them in place or if I am real careful on installation will the thrust buttons stay in place? Thanks!
Should be interesting to see if they hold up.
 

fontleyroy

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The axle will hold them in place unless the axle is pulled out again. They stick to the end of the axle when pulling it out. Dr. Diff has new ones with the pin that holds the buttons together.
Thanks, that's what I was hoping. Case number is 2070742 and based on counting the rotations its a 3.55. This rear can be identified as a power loc because of the thrust buttons? The other sure grip doesn't use them correct?
 

wvmarv

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Could have packed them with a grease cone before install but didn't think of it. I have a grease needle that works well to fill all the cavities. Just squeeze it in one end till it comes out the other.
No need to pack those bearings they are greased by the 90w grease you put in rear end.
 

threewood

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Great info on here. I just pulled my rear out as this is the third time I will replace the drivers side inner seal. Sure enough, the two thrust buttons and broken pin were sitting in the bottom of my pumpkin. This of course allowed the drivers side axle way too much play back and forth ruining the inner seal. My question is: Will I have to replace that broken pin to keep them in place or if I am real careful on installation will the thrust buttons stay in place? Thanks!
When I re-installed the axles into the housing, I glued the thrust button to the end of one axle. This was an Eaton TruTrac that had floating button.
 

threewood

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No need to pack those bearings they are greased by the 90w grease you put in rear end.

The outer bearings use grease. The inner seals are there to keep the 90w out of the bearings. If you have 90w gear oil in the outer bearings, your inner seals are bad.
 

wvmarv

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The outer bearings use grease. The inner seals are there to keep the 90w out of the bearings. If you have 90w gear oil in the outer bearings, your inner seals are bad.
Yep you're right. My old memory slipping.
 

64 Sportfury

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Just want to thank Threewood for the inspirational post. I followed the instructions as posted and successfully replaced my howling axle bearings.
 

Billccm

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I wimped out and had Tucson Differential do my axles, but used this thread as a reference when pulling the axles and replacing the seals.
 

64 Sportfury

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I considered having the axles done by a nearby shop as well but I have the time and the tools to give it a shot. We all know that satisfying feeling of doing something successfully.
 

HS 69 Charger

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I have read through this thread and really appreciate the huge amount of information. I have pulled my axels and Diff and now ready to source some parts. But have questions on parts and options. I don't have a press so i will have to partner with a local shop but i would like to identify the parts for my needs and have them ready for the work to be performed. My Charger is for cruising and shows and is nearly factory original. So I don't have special interest or needs. So Here are my questions:

Axel, I went to DiffDoctor and Summit Racing.
  • At Diff Doctor they are showing Timken and Precision but no stock on Timken which is the brand stamped on the bearings I have.
  • At Summit they are showing Yukon and a Mopar kit but it appears to be the "green" style bearing with no adjustment needed. i feel like I would prefer to just stick with the Original Tapered Bearings. The Yukon appears to be original Tapered using current adjusters.
Differential
  • I have two: One is the original 489 case with a SureGrip in place. It was pulled from the car some 40 years ago due to Howling noise. I simply was a high school student dependant on the car with little money so swapped in the first diff from a junkyard i could find which was a standard diff in a 741 Case. It is installed now but making howling noise. I want to move back to a SureGrip and am in a much better financial position now....
  • So want to use the 489 Case and would expect after all this age and known previous failure should just swap in a new SureGrip unit. And now we are back to which brand/unit and what are the Pros/Cons.
  • Beyond the SureGrip, i expect I should get new bearings and ??? (what else to prep the Diff for reassembly)
  • Last Choice/Question: My original Build Sheet shows my car came with 3.23 Ring Gear. (in 489 case). Currently it has a 2.76 Ring Gear and the other diff has a ~2.9 (estimate from turning wheel). Since i am actually planning road trips and just cruising do i really need to swap out the Ring Gear or simply use one of the current ones. Lots of opinion on that one.
Thanks for this great thread. it did give me the confidence to start and now hoping to learn what is needed to get to the finish.
Martin
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RJRENTON

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I have read through this thread and really appreciate the huge amount of information. I have pulled my axels and Diff and now ready to source some parts. But have questions on parts and options. I don't have a press so i will have to partner with a local shop but i would like to identify the parts for my needs and have them ready for the work to be performed. My Charger is for cruising and shows and is nearly factory original. So I don't have special interest or needs. So Here are my questions:

Axel, I went to DiffDoctor and Summit Racing.
  • At Diff Doctor they are showing Timken and Precision but no stock on Timken which is the brand stamped on the bearings I have.
  • At Summit they are showing Yukon and a Mopar kit but it appears to be the "green" style bearing with no adjustment needed. i feel like I would prefer to just stick with the Original Tapered Bearings. The Yukon appears to be original Tapered using current adjusters.
Differential
  • I have two: One is the original 489 case with a SureGrip in place. It was pulled from the car some 40 years ago due to Howling noise. I simply was a high school student dependant on the car with little money so swapped in the first diff from a junkyard i could find which was a standard diff in a 741 Case. It is installed now but making howling noise. I want to move back to a SureGrip and am in a much better financial position now....
  • So want to use the 489 Case and would expect after all this age and known previous failure should just swap in a new SureGrip unit. And now we are back to which brand/unit and what are the Pros/Cons.
  • Beyond the SureGrip, i expect I should get new bearings and ??? (what else to prep the Diff for reassembly)
  • Last Choice/Question: My original Build Sheet shows my car came with 3.23 Ring Gear. (in 489 case). Currently it has a 2.76 Ring Gear and the other diff has a ~2.9 (estimate from turning wheel). Since i am actually planning road trips and just cruising do i really need to swap out the Ring Gear or simply use one of the current ones. Lots of opinion on that one.
Thanks for this great thread. it did give me the confidence to start and now hoping to learn what is needed to get to the finish.
Martin
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Regarding a source for the Timken bearings (both the CUP or race and the CONE or roller assembly) including the seals and retainer required, HAVE you considered an industrial power transmission house, like Motion Industries or Bearings Incorporated. Both are national firms that deal with ALL forms of power transmission components, ranging from belts, sheaves, gear box assemblies, ALL types and brands of anti friction bearing assemblies (tapered, single row ball, spherical, straight roller, pillow block, tapered adapter mounted type, etc), perhaps you can source the components you need, by the part number on your existing parts. Not exactly know your location, so I cannot recommend a supply firm near your location, outside of the two you sources stated. Both of your stated suppliers PURCHASE and resell what they supply from others and just mark up the price. Just my opinion of course.
BOB RENTON
 

HS 69 Charger

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Regarding a source for the Timken bearings (both the CUP or race and the CONE or roller assembly) including the seals and retainer required, HAVE you considered an industrial power transmission house, like Motion Industries or Bearings Incorporated. Both are national firms that deal with ALL forms of power transmission components, ranging from belts, sheaves, gear box assemblies, ALL types and brands of anti friction bearing assemblies (tapered, single row ball, spherical, straight roller, pillow block, tapered adapter mounted type, etc), perhaps you can source the components you need, by the part number on your existing parts. Not exactly know your location, so I cannot recommend a supply firm near your location, outside of the two you sources stated. Both of your stated suppliers PURCHASE and resell what they supply from others and just mark up the price. Just my opinion of course.
BOB RENTON
I had not considered the "source" for direct part acquisition so I will explore that avenue.
Cass at Diff Doctor gave me some great info on troubleshooting and some part options. Summit also gave me their part options and found complete kits by Yukon on the Axels (seals, end plate, bearing, race, retainer) and on the Diff (main and pinion bearings, shims, etc) with two options on replacing the SureGrip (Auburn and Detroit Locker).
I stopped down to the local shop and he inspected my diff and axel. After exploring the labor time and pros/cons of rebuilding the SureGrip compared to replacing, I simply decided to just replace. I had the additional challenge of my preferred Diff was the one off the vehicle for the last 40yrs, so was impossible to troubleshoot without cleanup, installation, reproducing original problem, and then tearing it all down again. So the complete replacement route seemed best.
So now with a plan in place, I can take an extra step to see if I find direct part access that might trim down the price.
Although, I am using a local specialist to do the rebuild, this post at least gave me the confidence to pull it all apart and prep for work. A small savings of labor but also part of the fun.
Thanks again,
Martin
 

Mr. Cranky

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I had not considered the "source" for direct part acquisition so I will explore that avenue.
Cass at Diff Doctor gave me some great info on troubleshooting and some part options. Summit also gave me their part options and found complete kits by Yukon on the Axels (seals, end plate, bearing, race, retainer) and on the Diff (main and pinion bearings, shims, etc) with two options on replacing the SureGrip (Auburn and Detroit Locker).
I stopped down to the local shop and he inspected my diff and axel. After exploring the labor time and pros/cons of rebuilding the SureGrip compared to replacing, I simply decided to just replace. I had the additional challenge of my preferred Diff was the one off the vehicle for the last 40yrs, so was impossible to troubleshoot without cleanup, installation, reproducing original problem, and then tearing it all down again. So the complete replacement route seemed best.
So now with a plan in place, I can take an extra step to see if I find direct part access that might trim down the price.
Although, I am using a local specialist to do the rebuild, this post at least gave me the confidence to pull it all apart and prep for work. A small savings of labor but also part of the fun.
Thanks again,
Martin
Do you know what type of SureGrip you have? If it came out of the car in your avatar, it should be a cone unit but after 50+ years, someone could have installed the plate type. The clutch plate type can be 'rebuilt' and parts are available but the cone unit does not have any rebuild kits. ChryCo didn't intend for them to be rebuilt but if they are not total junk, they can be 'machined' and get a new life. Been doing that for a lot of years so if it is a cone type, don't throw it in the junk pile until you split it open and inspect the internals.
 

HS 69 Charger

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Do you know what type of SureGrip you have? If it came out of the car in your avatar, it should be a cone unit but after 50+ years, someone could have installed the plate type. The clutch plate type can be 'rebuilt' and parts are available but the cone unit does not have any rebuild kits. ChryCo didn't intend for them to be rebuilt but if they are not total junk, they can be 'machined' and get a new life. Been doing that for a lot of years so if it is a cone type, don't throw it in the junk pile until you split it open and inspect the internals.
Thanks for the extra info. While I am chosing to replace, I will hold onto the original and consider who in my car club can take advantage of it. I believe it is factory original but will inspect when its torn apart.
Thanks for the extra wisdom.

Martin
 

440 Charger

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Do you know what type of SureGrip you have? If it came out of the car in your avatar, it should be a cone unit but after 50+ years, someone could have installed the plate type. The clutch plate type can be 'rebuilt' and parts are available but the cone unit does not have any rebuild kits. ChryCo didn't intend for them to be rebuilt but if they are not total junk, they can be 'machined' and get a new life. Been doing that for a lot of years so if it is a cone type, don't throw it in the junk pile until you split it open and inspect the internals.
Sure grip are ok but now there is better.
 

threewood

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When you one that's good and working.....what's better? The only thing that's better imo isn't that easy to drive with on the street.

I would give the nod to an Eaton Trutrac over the stock sure grip. No need for additives and they are quiet. I have one in each car, 8 3/4 with 741 in both.
 
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